Control for rotary piston machines



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CONTROL FOR ROTARY PISTON MACHINES Filed Aug. 2'7, 1959 3 Sheets-Sheet 3 Fly. 8 Fig. 9

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i 4, x 1 4 A i 47' 7\ 5 I 57 46 I 53 {5 58 1 4ar 3 44 55 1 f5 9 I 3 g 69"\ x 56 54 53 5 42 Z 6 7/ 5 I 39 72 In v e n fo r United tates ate The present invention relates to the control of rotary pistonmachineshaving two rotary pistons one being arranged in the other. The control of such rotary piston machines is effected by controlelements arranged outside said rotary pistons. In this connection the control of the inlet and outlet openings may be effected for instance through stationary openings in the housing of the rotary piston machine if a change in the control points is not required. If, however, the control points are to be adjusted in conformity with the respective status of operation, the situation becomes considerably more difiicult.

Heretofore known controldevic'es employed for varying the control points used an annular member coaxially arranged around the outer rotor and rotatable thereabout while carrying the inlet and outlet openings. If desired, instead of a full annular member also a segment may be used for the purpose involved.

According to other suggestions dealing with the problem of adjusting or changing the control points, control discs have been employed which are rotatably arranged adjacent the rotors.

It has also been proposed for purposes of varying or adjusting the control points to employ rotatable bushings in the hollow rotor shaft if the Working fluid is passed through the hollow shaft into the working chamber or discharged therethrough.

II For the sake of completeness it may also be mentioned that a rotary piston machine has been known which is provided with two rotary control members for the work'- ing medium inlet and outlet respectively, said control members being arranged at an end face of the machine and rotating together with the machine shaft while being provided with non-variable inlet and outlet openings adapted to register with openings in the cylinder walls.

The above outlined controls for controlling rotary piston machines have the drawback that with only one of such control elements for the inlet and outlet it is not possible to adjust the control edges individually, i.e. independently of each other. To the contrary, all control points are always adjusted uniformly and in the same direction. However, inasmuch as it is possible in rare instances only, when designing a rotary piston machine, especially a high speed rotary piston machine, to consider at the start all influences or factors for the most favorable location of the control edge, the above mentioned defect of the heretofore known controls for rotary piston machines seriously affects the construction of rotary piston machines with high degree of efiiciency and with smooth running properties even at high speed. Furthermore, with rotary piston machines, constructions may be desired in which the individual displacement of the individual control points may be a requisite already due to the particular working method involved.

It is, therefore, an object of the present invention to provide a control for rotary piston machines which will overcomethe above mentioned drawbacks.

It' is another object of this invention to provide a rotary piston machine with control means which will make it possible to adjust the control edges independently of each other duringthe standstill as well as during the operation ofthe machine. 4 I

These and other objects and advantages of the invention will appear more clearly from the following specifi- 2 cation in connection with the accompanying drawings, in which: I

FIG. 1 diagrammatically illustrates a cross section through a rotary piston machiueworking as a compressor.

FIG. 2 illustrates by Way of a graph how two control edges, for instance with a rotary piston compressor of FIG. 1, would have to be adjusted if with varying deliveries and constant end pressure the said compressor would have to be operated at a maximum degree of'efiiciency.

FIG. 3 illustrates a longitudinal section through a coin pressor according to the invention with a two-tooth inner piston and three-tooth outer piston and with two rotatable control members around the outer rotor.

FIG. 4 is a section along the line IV-IV of FIG. 3.

FIG. 5 is a section along the line V-V of FIG. 3.

FIG. 6 represents a longitudinal section through a modified rotary piston compressor according to the invention having a control disc and being provided with a control ring around the outer rotor.

FIG. 7 is a section along the line YIIVII of FIG. 6.

FIG. 8 is a further modification of a rotary piston compressor according to the invention which is provided with a control cylinder in the hollow shaft of the machine and with a control ring extending around the outer rotor.

FIG. 9 is a section along the line IXIX of FIG. 8.

Referring now to the drawings, FIG. 1, as mentioned above, represents a cross section through a rotary piston machine working as compressor, whereas FIG. 2 illustrates how two control edges, for instance with a rotary piston compressor of FIG. 1, would have to be adjusted it with varying deliveries and constant end pressure the compressor would have to be operated at a maximum degree of etfi'c'ienc'y. The illustration of FIG. 2 merely concerns the control edge at the end of the suction and the begin ning of the compression step and also the control edge at the end of the compression and the start of the exhaust stroke. It should, therefore, be possible to vary the locations of these two control edges in circumferential direction in conformity with the respective delivery. It will be evident from FIG. 2 that between the relative locations of these edges there exists no relationship, which locations could be obtained by a single rigid element, as for instance by the control ring R of FIG. 1.

The locations of the two other control edges, namely the start of the suction and end of the exhaust stroke, are preferably also made variable. However, iii most instances it will sufiice to ascertain these last mentioned edges once and for all by tests and to fi'x the same for instance during the standstill of the machine.

The present invention is based on my finding that each control edge of the inlet and outlet opening respectively has to be adjusted in a continuous manner during the operation within the frame work of the control operation, whereas each other associated control edge has to be adjusted once, namely when adjusting the machine. Furthermore, the control openings must be so dimensioned that also at the maximum mechanically obtain able working speeds no harmful choking will occur. This last mentioned requirement may be of particular importance when arranging the control openings and edges in outer or inner rings or discs.

In order to materialize the above outlined objects, the present invention makes use of a rotary piston machine with two rotatable control rings or segments extending over the outer rotor. There may also be used a rotary piston machine with two control cylinders or cylinder portions rotatably arranged in the hollow shaft of the inner rotor, in such instance, the rings or cylinders o'r segments or cylinder portions may be located adjacent each other in axial direction. If desired, also a rotary piston machine may be employed with two adjustable control discs which are arranged at the end face of the 3 rotor and which are equipped with the required openings or control edges. Naturally, also combinations of the above mentioned control members may be employed in such a way that for instance a control disc cooperates with a control disc or control ring extending around the outer rotor.

Referring now to the rotary piston compressor shown in FIGS. 3 to 5, the compressor illustrated therein comprises primarily an annular housing 1 with the two lateral housing portions 2 and 3. These two lateral housing portions 2 andfi3 have fixedly connected thereto bearing discs 4 and 5 respectively. The two-tooth inner rotary piston 6 journalled in the bearing discs 4 and 5 is rotated through the intervention of a shaft 7. The outer three-tooth rotary piston 8 comprises the annular rotor 8 proper and the end discs 9 and 1t) fixedly connected thereto. The end discs 9 and 10 are rotatably mounted on the bearing discs 4 and 5 forming the bearings therefor.

The outer rotary piston 8 is driven through the intervention of a gear 12 keyed to the shaft stud 11 of the inner rotor 6 and through the intervention of the gear ring 13 meshing with the gear 12 and fixedly connected to the end disc 9. The two rotary pistons 6 and 8 form with each other the working chambers 14, 15 and 16 (FIGS. 4 and 5) which respectively communicate with the suction and the pressure chambers through windows 17, 18 and 19. The compressor is sealed by means of sealing elements 20 arranged on the inner side of the bearing discs 4 and 5. Housing 1 is provided with a circular suction chamber 22 which, as will be evident from the drawings is located between the radially extending partitions 110, 111 (FIG. 5) and extends over the entire Width of the housing. The pressure chamber- 23 extending over a short portion only of the circumference extends over half the width of the housing and is separated from suction chamber 22 by means of partitions 111, 110 and the partition 21 extending in circumferential direction. These chambers respectively communicate with a suction connection and a pressure connection.

The housing 1 further comprises two control rings 24 and 25 which extend around the rotor 8. The ring 24 representing the suction control ring, and the ring 25 representing the pressure control ring are arranged adjacent each other and are adapted to be adjusted for instance by means of spur gears 26, 27 rotatably journalled in the lateral housing portions 2 and 3 and meshing with gear rings 28 and 29 respectively of the control rings 24 and 25. The said spur gears 26, 27 are adapted to be rotated from the outside of the housing by adjusting levers 30 and 31 respectively. It is, however, to be understood that the adjustment of the control rings may also be effected in any other convenient manner either manually or by a governor connected thereto. By means of any suitable transmission, the adjusting angles of the control rings may be coordinated with each other in linear or any other suitable manner.

FIG. 4, which represents a radial section through the suction chamber of the compressor of FIG. 3, clearly shows the suction control ring 24 with the control edge 33 determining the end of the suction stroke, and with the control edge 34 determining the start of the suction stroke. The increasing working chamber 15 is drawing in the fluid from suction chamber 22 through the window 18 in the outer rotary piston, the working chamber 16 has reached its maximum value, and window 19 has just passed over the control edge 33 determining the end of the intake stroke. As will be evident from FIG. 5 representing a radial section through the pressure chamber of the compressor, the window 17 of the decreasing working chamber 14 has partially passed over the control edge 35 of the pressure control ring 25, which edge 35 determines the end of the compression and the start of the exhaustion. The compressed fluid will thus be discharged into the pressure chamber 23. The pressure control ring 25 has associated therewith a stationary annular section or segment 32 provided with a control edge 36 determining the end of the discharge stroke. When setting the machine, said annular section 32 may first be displaced somewhat in circumferential direction and may then be arrested and held in the respective position to thereby set the control point for the end of the discharging stroke in conformity with the respective requirements. By prematurely finishing the discharge stroke and due to the back expansion inherent thereto of the compressed but not discharged working medium, the degree of efiiciency and the running smoothness of the machine may be improved.

FIG. 6 illustrates a modified rotary piston compressor with a three-tooth outer rotary piston 37 and a four-tooth inner rotary piston 38, said two pistons rotating in the same direction. The inlet of this compressor is controlled by a control ring 39 surrounding the outer rotor 37, Whereas the outlet is controlled by a control disc 41 arranged adjacent one end disc 40 of the outer rotor 37. The other end disc 42 which, similar to the end disc 40, is connected to the annular portion of the outer rotor 37 is connected to the flange 43 of the input shaft 44. Input shaft 44 is journalled in a flange-like bearing member 45 which is connected to the housing 46. The open side of the housing 46 is closed by a lateral portion 47 having a bearing stud 48 eccentrically arranged with regard to shaft 44. The inner rotor 38 is rotatably journalled on stud 48. The inner rotor 38 is adapted to-be rotated by means of a spur gear 49 connected to the inner side of flange 43 and meshing with a gear ring 50 which is arranged on the inner side of a sleeve-like extension of the inner rotor 38. Stud 48 is provided with an eccentric disc 51 which is arranged coaxially with regard to the axis of shaft 44 and also with regard to the outer rotor 37. The control disc 41 is rotatably journalled on disc 51. The central portion of the housing 46 which communicates with the suction connection forms the suction chamber 52, Whereas the lateral portion 47 carrying the pressure connection forms the pressure chamber 53.

As will be evident from FIG. 7, the inner rotor 38 and the outer rotor 37 form with each other three working chambers 54, 55 and 56 which communicate with the suction chamber 52 through Windows 57, 58 and 59 in the outer rotor. The end disc 40 of the outer rotor 37 has three openings 60, 61 and 62 which form outlets for the working chambers. The compressed working medium is discharged through the control opening 63 of control disc 41 whenever one of the disclosure openings 60, 61, 62 registers with the control opening. The suction control ring 39 comprises a control edge 70 determining the intake start and also comprises a control edge 71 determining the end of the intake stroke. For purposes of adjusting the suction control ring 39, the latter has one of its end faces provided with a gear ring 64 meshing with a gear 65 the shaft of which is rotatably journalled in housing 46 and is adapted to be rotated by means of the adjusting lever 66 connected thereto. The adjustment of the control disc 41 is effected by means of a control lever 67 and by means of a gear 68 meshing with a gear ring 69 of the control disc 41. The rotary pistons are sealed with regard to each other by sealing elements 72.

As will be evident from FIG. 7, with the elements in the position shown therein, the increasing working chamber 55 is taking in the working medium from suction chamber 52 through windows 58 of the outer rotor 37, whereas the working chamber 56 has reached its maximum value and has just passed by the control edge 71 determining the end of the intake step. The outlet opening 60 of the end disc 40 associated with the chamber 56, has just started to pass by the control opening 63 of the control disc 41 and is enabling the pressure fluid to pass 'into the pressure chamber 53.

With the rotary piston compressor illustrated in FIGS. 8 and 9, the inlet of the working medium is efiected through the outer rotor 76 and a control ring 73 surrounding said outer rotor, whereas the outlet is eflected through the inner rotor 83, the control sleeve 74 and the hollow shaft 75. The three-tooth outer rotor 76 comprises a cylindrical central portion 76a and the lateral discs 77 and 78. The disc 78 is connected to flange 79 of the input shaft 80 which is rotatably journalled in a bearing flange 81 of the housing 82. The four-tooth inner rotor 83 is rotatably journalled on a control sleeve 74 which in its turn is rotatably journalled on hollow shaft 75. Hollow shaft 75 serves as discharge means for the compressed working medium and is connected to the lateral portion 84 of the housing 82. Centrally located in flange 79 is a spur gear 85 which meshes with a gear ring 86 arranged in a sleeve-like extension of the inner rotor 83, thereby driving the inner rotor 83. For purposes of adjusting the control edges, control ring 73 has one of its end faces provided with a gear ring 87 meshing with a gear 88 which is rotatably journalled in housing 82 and adapted to be rotated by means of a control lever 89. In order also to be able to adjust the control sleeve 74, the latter has its outer end provided with a gear ring 90 meshing with a gear 91 which is rotatably journalled in the housing lateral member 84 and which may be rotated by means of a control lever 92. FIG. 9 shows the working chambers 93, 94 and 95 confined by the two rotors, and also shows the inlet openings 96, 97 and 98 in the outer rotor 76 and also shows the outlet openings 99, 100, 101 and 102 in the inner rotor 83. Also evident from FIG. 9 are the annular suction chamber 103 formed by the housing 82, the suction control ring 73 with the control edge 104 determining the start of the intake step, and the control edge 105 determining the end of the intake step. The adjustable control sleeve 74 is provided with a controledge 106 determining the end of the compression and the start of the exhaust step. The end of the exhaust period is determined by control edge 107 of the stationary hollow shaft 75. This control point is determined when first setting the machine and is fixed by rotating the hollow shaft 75. The hollow shaft will be fixed in this position. The sealing of the rotors with regard to each other will be effected by sealing elements 108.

In the particular position shown in FIG. 9, the increasing chamber 93 will through opening 96 in the outer rotor take in the working medium from the suction chamber 103. Chamber 95 has reached its maximum value, and opening 97 of the outer rotor has just passed by the control edge 105 determining the end of the intake step of the control ring 73. FIG. 9 furthermore shows that in the chamber 95 which is decreasing, the working medium will be compressed. The outlet opening 101 of the inner rotor 83 is about to pass over the control edge 106 determining the start of the exhaust, and to release the passage for the working fluid into the hollow shaft 75, whereas the outlet opening has almost passed the control edge 107 determining the end of the outlet stroke.

The various controls described above make it possible with rotary piston machines having rotary pistons eccentrically arranged with regard to each other to vary those control points which are important for the output control of the machine independently of each other, namely the start of the inlet and, in particular, the end of the inlet as well as the start of the discharge thereby permitting control of the quantity of the taken-in and thus delivered working medium as well as the compression end pressure. By means of control devices known per se, the adjustments of the control points can, in conformity with the requirements of operation, be effected independently of each other or in any desired manner.

It is, of course, to be understood that the present invention is, by no means, limited to the particular constructions shown in the drawings but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. In a rotary piston compressor: a housing, inlet and outlet passage means in said housing axially spaced from each other, an outer rotor rotatable in said housing, an inner rotor inside the outer rotor rotatable on an axis parallel with the axis of rotation of the outer rotor and spaced therefrom, said inner rotor having teeth about the outer periphery, said outer rotor having teeth on the inner periphery and the number of teeth on said outer rotor and inner rotor differing from each other by one, the cavity in the outer rotor constituting a volume of revolution defined therein by the inner rotor when the rotors rotate in the same direction at a predetermined speed differential, passages in the outer rotor leading outwardly from between the teeth therein and of such width as to be able to communicate with both of said inlet and outlet passages in the housing, two arcuate control members in side by side relation in the housing interposed between the hous ing and the outer rotor and surrounding said outer rotor, each control member being provided with a circumferentially extending aperture communicating with the passages in the outer rotor as the outer rotor rotates and also communicating with a different one of the inlet and outlet passages in the housing, and means for adjusting said control members angularly in the housing about the axis of said outer rotor to adjust the circumferential region in which the passages in the outer rotor communicate with the inlet and outlet passages, respectively, in the housing.

2. In a rotary piston compressor with outer rotary piston means having internal teeth and inner rotary piston means in said outer rotary piston means having external teeth, said piston means being rotatable on parallel axes and confining with each other working chambers, the outer piston being provided with inlet and outlet passage means communicating with said Working chambers for the working medium to be conveyed to and from said working chambers; the improvement which comprises, first control means and second control means respectively associated with said passage means for respectively controlling the areas of said inlet and outlet passage means for varying the volume of the delivered gas, said first and second control means comprising two arcuate members each extending around said outer rotary piston and being arranged axially adjacent each other, said first and second control means defining control apertures having front control edges and rear control edges for establishing and interrupting said inlet and outlet passage means respectively, and adjusting means respectively connected to said first and second control means and operable individually and independently of each other for selectively adjusting said first and second control means individually and independently of each other angularly about said outer rotary piston, and a further adjustable control member forming a part of one of said arcuate members and normally adjusted only when setting the compressor and normally kept stationary in a fixed position during the operation of the compressor, said further adjustable member forming one of the control edges of the pertaining arcuate member.

3. In a rotary piston compressor: an outer rotary piston member and an inner rotary piston member therein, said piston members being rotatable in the same direcion and relative to each other on spaced parallel axes, said inner piston member having a predetermined number of teeth and said outer piston member having a number of teeth difiering by one from said predetermined number, said rotary piston members confining with each other working chambers, said piston members being provided with inlet and outlet passage means communicating with said chambers for the working medium to be conveyed to and from said working chambers, first control means and second control means for respectively controlling said 7 inlet and outlet passage means, one of said first and second control means comprising a hollow cylinder arranged within said inner rotary piston member and the other one of said first and second control means comprising an annular member extending around said outer rotary piston member, said first and second control means respectively being provided with apertures having front control edges and rear control edges for controlling the establishing and interrupting of said inlet and outlet passage means respectively, and adjusting means respectively operatively connected to said first and second control means and operable individually and independently of each other for selectively adjusting said first and second control means individually and independently of each other.

4. In a rotary piston compressor: an outer rotary piston member and an inner rotary piston member therein, said piston members being rotatable in the same direction and relative to each other on spaced parallel axes, said inner piston member having a predetermined number of teeth and said outer piston member having a number of teeth differing by one from said predetermined number, said rotary piston members confining with each other working chambers, said piston members being provided with inlet and outlet passage means communicating with said chambers for the working medium to be conveyed to and from said working chambers, first control means and second control means for respectively controlling said inlet and outlet passage means, one of said first and second control means comprising a hollow cylinder arranged Within said inner rotary piston member and the other one of said first and second control means comprising disc means arranged adjacent an end face of said rotary piston members, said first and second control means respectively being provided with apertures having front control edges and rear control edges for controlling the establishing and interrupting of said inlet and outlet passage means respectively, and adjusting means respectively operatively connected to said first and second control means and operable individually and independently of each other for selectively adjusting said first and second control means individually and independently of each other.

5. In a rotary piston compressor: an outer rotary piston member and an inner rotary piston member therein, said piston members being rotatable in the same direction and relative to each other on spaced parallel axes, said inner piston member having a predetermined number of teeth and said outer piston member having a number of teeth differing by one from said predetermined number, said rotary piston members confining with each other working chambers, said outer piston member being provided with inlet passage means communicating with said chambers for the working medium, there being outlet passage means leading from said working chambers at one end face of said piston members, first control means and second control means for respectively controlling said inlet and outlet passage means, one of said first and second control means comprising disc means arranged adjacent said one end'face of said rotary piston members, and another one of said first and second control means comprising an annular member extending around said outer rotary piston member, said first and second control means respectively being provided with apertures to communicate with said passage means and having front control edges and rear control edges for controlling the establishing and interrupting of said inlet and outlet passage means respectively, and adjusting means respectively operatively connected to said first and second control means and operable individually and independently of each other for selectively adjusting said first and second control means individually and independently of each other.

References (iited in the file of this patent UNITED STATES PATENTS .Re. 24,064 Welch Sept. 20, 1955 1,482,807 Newberg Feb. 5, 1924 1,616,992 Ruckstuhl Feb. 8, 1927 1,948,907 Egli Feb. 27, 1934 2,580,006 Densham Dec. 25, 1951 2,688,927 Nuebling Sept. 14, 1954 2,898,862 Brundage Aug. 11, 1959 r 2,925,044 Brundage Feb. 16, 1960 2,956,506 Brundage Oct. 18, 1960 FOREIGN PATENTS 511,086 France Sept. 18, 1920 1,024,196 Germany Feb. 13, 1958 (ApplicationKl. 27c 6/03) 

